1. Field of the Invention
The present invention relates to a binding device, and in particular, for example, to a binding device used for a ring binder or file.
2. Description of the Related Art
A conventional binding device is configured such that an approximately annular binding ring is engaged at its center so as to be closed. For example, if the ring is manually opened or closed, a pair of approximately semicircular binding half rings which together define an approximately annular binding ring are pulled apart with fingers so as to be separated from each other, thereby opening the binding ring.
When the approximately annular binding ring is opened with fingers, however, it is difficult to open the pair of approximately semicircular binding half rings defining the binding ring when a relatively large number of sheets of a document are bound.
Therefore, for example, a ring file disclosed in Japanese Patent Laid-Open Publication No. Hei 10-337988 has been proposed.
The so-called lever type binder of a conventional ring file disclosed in the above-cited patent publication, however, has the following problem. When a large amount of an object is to be bound by approximately annular binding rings of the ring file, the inner sides of levers are pushed outwardly and down so as to open the binding rings. However, when the levers are pushed outwardly and down from the bound article side so as to open the binding rings, the bound article is an obstacle, which makes it difficult to push down the levers with fingers.